Hard ferrites are magnetic ceramics which retain permanent magnetism and find application in both electronic and non-electronic sectors. Today, ferrite magnets have the largest usage in terms of tonnage in energy-related applications, which is attributed to their low price. For many applications, a permanent magnet is the best choice because it provides a constant field without the continuous expenditure of electric power and without generation of heat. Strontium hexaferrite (SrFe12O19, Sr-ferrite) is one well-known material for permanent magnets. It is a hard magnet with high coercivity, and can be used as permanent magnets, recording media, telecommunication, as well as in microwave components, higher-frequency components, and magneto-optical devices.
In another aspect, the quantity of iron oxide by-products are increasing rapidly with the rising demand for steel production. These by-products are underutilized and are often disposed of. The safe disposal of these by-products is expensive and continues to be a serious concern in many countries throughout the world. Thus, there remains a strong need in the art for alternative methods of making hard magnet materials using iron oxide by-products.